With the growing interest in energy conservation, increasingly more industrial work machines are supplied with electric drive assemblies or systems for driving the work machine and operating its various tools or functions. Ongoing developments in electric drive systems have made it possible for electrically driven work machines to effectively match or surpass the performance of predominantly mechanically driven work machines while requiring significantly less fuel and overall energy. As electric drive systems become increasingly more commonplace with respect to industrial work machines, and the like, the demands for more efficient motors, generators and techniques for controlling same have also increased.
An electric motor of an electric drive machine is typically used to convert mechanical power received from a primary power source, such as a combustion engine, into electrical power for performing one or more operations of the work machine. Additionally, an electric motor may be used to convert electrical power stored within a common bus or storage device into mechanical power. Among the various types of electric motors available for use with an electric drive system, switched reluctance machines have received great interest for being robust, cost-effective, and overall, more efficient. While currently existing systems and methods for controlling switched reluctance machines may provide adequate control, there is still much room for improvement.
Control schemes for switched reluctance machines may typically involve operating two switches of each phase leg of the machine to pulse or chop the electrical current thereby effectively providing a waveform, such as a pulse width modulated PWM waveform. Toward the end of a given switching period or fundamental cycle, upon reaching a current target threshold, or when there is an otherwise corresponding decrease in current demand, both switches of a particular phase leg of the machine in conventional control systems may be disabled. Conversely, at the beginning of a given switching period or fundamental cycle, upon reaching a current target threshold, or when there is an otherwise corresponding increase in current demand, both switches of a particular phase leg of the machine in conventional control systems may be enabled. Disabling or enabling both switches of a phase leg can expose the phase windings to abrupt and high magnitude voltage swings which can further cause excessive wear to the winding insulation of the associated switched reluctance machine and other undesirable effects.
The present disclosure is directed at addressing one or more of the deficiencies set forth above.